Electroluminescent display for a timepiece

Abstract

An illuminated date ring for a calendar wristwatch for viewing the date at night through a window in the dial, employs an electroluminescent (EL) lamp beneath a transparent date ring. The EL lamp electrodes extend around the ring, and flexible spring members make sliding contact with the electrodes as the ring rotates in the movement.

We claim: 
     
       1. An improved electroluminescent display for a timepiece having a dial with a window therein and having a movement adapted to provide a rotational movement to a ring adapted to be periodically rotated beneath said dial window, said display comprising: a drive circuit for an electroluminescent display, including means for selectively actuating the drive circuit,   a ring of transparent insulating material having a sequence of indicia on the upper surface thereof, said ring being disposed beneath said dial for rotation by the movement,   at least one electroluminescent lamp disposed on the underside of said ring beneath said indicia,   first and second electrodes connected to the electroluminescent lamp and extending continuously around the ring, and   a pair of electrically conductive members connected to the drive circuit and arranged to make sliding electrical contact with the first and second electrodes as the ring rotates.   
     
     
       2. The combination according to claim 1, wherein the electroluminescent lamp comprises a multilayered structure applied to the underside of said ring, and extending continuously around the ring. 
     
     
       3. The combination according to claim 1, wherein the pair of electrically conductive members are flexible spring members. 
     
     
       4. The combination according to claim 1, wherein the ring is a calendar date ring and the indicia comprise numerals. 
     
     
       5. The combination according to claim 1, wherein the ring is a day ring and wherein the indicia comprise days of the week. 
     
     
       6. An improved electroluminescent display for a timepiece having a dial with a window therein and having a movement adapted to provide a rotational movement to a ring adapted to be periodically rotated beneath said dial window, said display comprising: a drive circuit for an electroluminescent display, including means for selectively actuating the drive circuit,   a ring of transparent insulating material having a sequence of indicia on the upper surface thereof, said ring being disposed beneath said dial for rotation by the movement,   a transparent conductive layer on the under surface of said ring,   a layer of electroluminescent material disposed on a portion of said conductive layer beneath said indicia,   a layer of insulating material disposed on said electroluminescent material,   a first electrode in contact with the conductive layer and extending continuously around the ring,   a second electrode in contact with the insulating material layer and extending continuously around the ring, and   a pair of electrically conductive members connected to the drive circuit and arranged to make sliding electrical contact with the first and second electrodes as the ring rotates.   
     
     
       7. The combination according to claim 1, wherein the first and second electrodes are layers applied to the conductive material layer and the insulating material layer respectively.